follow etcd leader

follow-leader.sh

#!/bin/sh

kill_daemon() {
        pid=$(getpid)
        if [ -n "$pid" ]; then
                echo "DEBUG: killing $pid" 1>&2
                kill $pid
                while kill -0 $pid 2>/dev/null; do
                        if ! sleep 1; then
                                trap EXIT
                                rm -f $pidfile
                                exit 1
                        fi
                done
        fi
}

getpid() {
        cat $pidfile
}

setpid() {
        pid=$(jobs -p)
        if [ -n "$pid" ]; then
                echo "DEBUG: $pid" 1>&2
                echo $pid > $pidfile
        fi
}

cleanup() {
        kill_daemon
        rm -f $pidfile
}
trap cleanup EXIT

pidfile=$(mktemp)
while true; do echo no redis leader; sleep 1; done &
setpid

bin/etcdctl watch --forever /leader | while read leader; do
        kill_daemon
        while true; do echo redis leader: $leader; sleep 1; done &
        setpid
done